Add Cancelation Test

Author: say25

src/PostgreSQLCopyHelper.Test/Issues/Issue58_CancelRequest_Test.cs

@@ -0,0 +1,85 @@
+using System;
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+using Npgsql;
+using NUnit.Framework;
+
+namespace PostgreSQLCopyHelper.Test.Issues
+{
+    [TestFixture]
+    [Description("A Unit Test to see, if PostgreSQLCopyHelper works with Canceling Requests.")]
+    public class Issue58_CancelRequest_Test : TransactionalTestBase
+    {
+        private class User
+        {
+            public int Id { get; set; }
+
+            public string Name { get; set; }
+        }
+
+        private PostgreSQLCopyHelper<User> subject;
+
+        protected override void OnSetupInTransaction()
+        {
+            CreateTable();
+        }
+
+        [Test]
+        public async Task Test_CanceledBulkInsertThrowsWhenCanceled()
+        {
+            subject = new PostgreSQLCopyHelper<User>("sample", "TestUsers")
+                     .MapInteger("Id", x => x.Id)
+                     .MapText("Name", x => x.Name);
+
+            var cancellationTokenSource = new CancellationTokenSource();
+
+            // Try to work with the Bulk Inserter:
+            try
+            {
+                cancellationTokenSource.CancelAfter(15);
+                await subject.SaveAllAsync(connection, FetchUserData(), cancellationTokenSource.Token);
+                Assert.Fail("Should Never Reach Here!");
+            }
+            catch (TaskCanceledException)
+            {
+            }
+            catch (Exception)
+            {
+                Assert.Fail("Should Throw Exception of Type TaskCanceledException!");
+            }
+            finally
+            {
+                cancellationTokenSource.Dispose();
+            }
+        }
+
+        private static async IAsyncEnumerable<User> FetchUserData()
+        {
+            for (var i = 1; i <= 2; i++)
+            {
+                // Simulate waiting for data to come through.
+                await Task.Delay(10);
+                yield return new User
+                {
+                    Id = i,
+                    Name = $"Username {i}"
+                };
+            }
+        }
+
+        private int CreateTable()
+        {
+            var sqlStatement = @"CREATE TABLE sample.TestUsers
+                                (
+                                    Id integer,
+                                    Name text                
+                                 );";
+
+            var sqlCommand = new NpgsqlCommand(sqlStatement, connection);
+
+            return sqlCommand.ExecuteNonQuery();
+        }
+    }
+
+}